function stringRev(str){
if (typeof str === 'string'){
var resultstring = '';
if (str.length % 2 === 0) {
for (let i=0; i<str.length; i=i+2){
let currentBlock = str.slice(i, i+2).split("").reverse().join("");
resultstring+=currentBlock;
}
} else {
for (let i=0; i<str.length-1; i=i+2){
let currentBlock = str.slice(i, i+2).split("").reverse().join("");
resultstring+=currentBlock;
}
resultstring+=str[str.length-1];
}
return resultstring;
} else {
return 'Wrong string';
}
}
console.log(stringRev('Helts'));
